Long-term Efficacy of Pectoserratus Plane Block (PSPB) for Prevention of Post-mastectomy Pain Syndrome: Extended Follow-up From a Randomized Controlled Trial.

OBJECTIVES: Pectoserratus plane block (PSPB) leads to lower postoperative pain intensity. We examined whether PSPB could also reduce the incidence of post-mastectomy pain syndrome (PMPS) in women undergoing breast cancer surgery. METHODS: We performed an extension study of a randomized trial that compared PSPB versus control in women undergoing mastectomy. The primary outcome was any chronic pain at the surgical site or adjacent areas, defined as persistent/recurrent pain lasting ≥3 months. Secondary outcomes included neuropathic pain (score ≥4 in the Douleur Neuropathique 4 questionnaire), use of analgesic/anti-inflammatory drugs, pain intensity through the short-form McGill Pain Questionnaire, and type, frequency, and location of the pain. RESULTS: Of the 60 patients that completed the 24-hour follow-up (short-term trial), 53 (88%) completed the long-term follow-up (27 in the PSPB group and 26 in the placebo group). Six of 27 patients (22%) in the PSPB group and 17 of 26 patients (65%) in the placebo group reported any chronic pain (relative risk [RR], 0.34; 95% confidence interval [95% CI]=0.16-0.73, P =0.005). The risk of neuropathic pain was also lower in the PSPB group than in the placebo group (18.5% vs. 54%, respectively; RR, 0.34; 95% CI=0.14-0.82, P =0.02). There were no differences regarding all other pain-related outcomes considering the patients who developed PMPS. DISCUSSION: The results suggest that, in the long term, PSPB-treated participants were associated with a statistically significantly lower risk of PMPS than those who received standard general anesthesia. TRIAL REGISTRATION: ClinicalTrials.gov (NCT03966326).

Intra-operative esmolol and pain following mastectomy: A randomised clinical trial.

BACKGROUND: Esmolol is a beta-1 selective blocker that has been shown to reduce postoperative pain. Its antinociceptive effects have not been tested following mastectomy. OBJECTIVE: To evaluate the safety, efficacy and antinociception of intra-operative esmolol infusion after mastectomy. DESIGN: Randomised, double-blinded, placebo-controlled trial. SETTING: Tertiary referral centre, Brasília, Brazil. Recruitment: July 2015 to July 2017. PATIENTS: Seventy women scheduled for mastectomy, ASA I to III, aged 18 to 75 years. Four were excluded. INTERVENTIONS: All underwent general anaesthesia. The intervention group received a bolus of 0.5 mg kg-1 of esmolol over 10 min followed by a continuous infusion of 100 µg kg-1 min-1. The placebo group received saline. MAIN OUTCOME MEASURES: The primary outcome was pain at rest 24 h after mastectomy as measured by a 0 to 10 numeric rating scale. RESULTS: Pain scores at rest 24 h after mastectomy were lower in esmolol-treated patients compared with placebo (mean difference = -1.51, 95% confidence interval (CI), -2.36 to -0.65, P = 0.001). On arrival in the postanaesthesia care unit (PACU), the occurrence of pain was also lower in the esmolol group, at rest and on effort (P = 0.009 and P = 0.013, respectively), on discharge from PACU (P = 0.009 and P = 0.015), 12 h (P = 0.01 and P = 0.007) and on effort in the 24 postoperative hours (P = 0.003). Mean morphine consumption was reduced by 77% in the esmolol group compared with the placebo group (mean difference  = -2.52 mg, 95% CI = -3.67 to -1.38, P < 0.001). The length of hospital stay was shorter for the esmolol group (mean difference = -6.9 h, 95% CI, -13.4 to -0.31, P = 0.040). CONCLUSION: Esmolol was well tolerated, allowed a notable reduction in the dose of rescue analgesics and demonstrated superior efficacy compared to placebo for pain management after mastectomy. TRIAL REGISTRATION: ClinicalTrials/NCT02466542.

Synergistic effect of the association between lidocaine and magnesium sulfate on peri-operative pain after mastectomy: A randomised, double-blind trial.

BACKGROUND: Recently, the use of venous adjuvants, such as lidocaine and magnesium sulfate, has been gaining ground in multimodal analgesia. However, no study has evaluated the impact a combination of the two drugs. OBJECTIVES: To evaluate the efficacy of venous adjuvants in reducing opioid consumption and pain scores after mastectomy. DESIGN: Randomised, double-blind, parallel-group, noninferiority clinical trial with a 1 : 1 : 1 : 1 allocation ratio. SETTING: Hospital de Base do Distrito Federal, Brasilia, Federal District, Brazil from November 2014 to December 2017. PATIENTS: One-hundred and ninety-eight patients were electively scheduled for mastectomy. Seventy-eight were excluded. INTERVENTIONS: Intra-operative infusions of remifentanil (0.1 µg kg min), lidocaine (3 mg kg h), magnesium sulfate (50 mg kg + 15 mg kg h) or lidocaine with magnesium sulfate were used. All patients received standard general anaesthesia. MAIN OUTCOME MEASURES: Peri-operative opioid consumption and pain scores. RESULTS: The patients who received both lidocaine and magnesium sulfate group (n=30) consumed less alfentanil during surgery (P < 0.001) and less dipyrone (P < 0.001) and morphine (P < 0.001) in the postoperative period. Only two patients (6.7%) in the lidocaine and magnesium sulfate group needed morphine (P < 0.001). These requirements were significantly lower when compared with patients who received remifentanil (n=30; 76.6%) and magnesium sulfate (n=30; 70%; odds ratio 46.0, 95% confidence interval 8.69 to 243.25, P < 0.001, and odds ratio 32.66, 95% confidence interval 6.37 to 167.27, P < 0.001, respectively). The patients of the lidocaine and magnesium sulfate group had lower pain scores in the first 24 h postoperatively using the numerical rating scale and verbal rating scale at discharge from the postanaesthesia care unit (P < 0.001), after 12 h (P < 0.001) and after 24 h (P < 0.001) when compared with the other three groups. CONCLUSION: Our findings suggest a synergistic effect of the use of both lidocaine and magnesium in peri-operative pain. This may be another potential strategy in the multimodal analgesia regimen. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT02309879.